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R K Olney

Publications and source records attributed to R K Olney.

54 records · Page 3Linked to original sources
PubMed1990

A comparison of thermography and electromyography in the diagnosis of cervical radiculopathy.

We studied 20 asymptomatic control subjects and 14 patients with clinically unequivocal cervical radiculopathy to compare the diagnostic value of thermography with that of electromyography. We measured the average skin temperature of designated regions over the neck, shoulder, and upper extremities. We then compared the temperature between corresponding regions of the two limbs, and between fingers innervated by different roots in the same hand. Thermography was abnormal in 6 patients (43%), whereas electromyography was abnormal in 10 (71%). Thermographic abnormalities were seen only in the hands and fingers, and the pattern did not follow the dermatome of the clinically involved cervical root. When compared to electromyography, thermography provided no additional diagnostic information. Thus, thermography does not have an established role in the evaluation of patients with cervical radiculopathy.

Arm↗
PubMed1990

Electrodiagnostic features of the Guillain-Barré syndrome: the relative sensitivity of different techniques.

We compared the diagnostic sensitivity of somatosensory evoked potentials (SEPs) and F waves with peripheral motor and sensory nerve conduction studies in 15 patients with the Guillain-Barré syndrome. All 4 types of studies were performed on 44 nerves (17 median, 12 ulnar, and 15 lower extremity). In the lower extremities, we used the peroneal nerves for all types of study except peripheral sensory conduction studies, which were performed on the sural nerve. We detected abnormalities by peripheral motor conduction studies in 33 of 44 nerves, by F waves in 31, by SEPs in 23, and by peripheral sensory conduction in 17. The cumulative sensitivity increased with the testing of multiple nerves by motor nerve conduction, sensory nerve conduction, and F-wave studies, but not with multiple SEPs. F-wave studies were significantly more sensitive than SEPs in identifying abnormalities. Thus, the recording of SEPs is indicated for diagnosis of the Guillain-Barré syndrome only if peripheral nerve conduction and F-wave studies are normal.

Adolescent↗
PubMed1989

Evaluation of thermography in the diagnosis of selected entrapment neuropathies.

We studied 20 normal subjects, 22 patients with carpal tunnel syndrome, and 15 with ulnar neuropathy at the elbow to compare the diagnostic accuracy of infrared thermography with that of conventional electrodiagnostic studies. We found abnormal thermograms in 55% of patients with carpal tunnel syndrome and 47% with ulnar neuropathy, using 2.5 SD from the normal mean as criteria for abnormality. The abnormalities consisted of either an increase in interside temperature difference in the fingers and hands or an alteration of the normal thenar-hypothenar temperature gradient in the fingers. The sensitivity of thermography was considerably lower than that of conventional electrodiagnostic methods. Moreover, the thermographic abnormalities were nonspecific, and could be misleading as they did not reliably identify the side of lesion or distinguish between median or ulnar nerve involvement. Thus, thermography is not helpful in the diagnosis of these two common entrapment neuropathies.

Carpal Tunnel Syndrome↗
PubMed1989

The role of thermography in the evaluation of lumbosacral radiculopathy.

We studied 27 normal subjects and 30 patients with low back pain to evaluate the diagnostic accuracy of thermography in the diagnosis of lumbosacral radiculopathy. Thermographic abnormality was defined as the presence of either interside temperature difference exceeding 3 standard deviations from the normal mean, or an abnormal heat pattern overlying the lumbosacral spine. In patients with clinically unequivocal radiculopathy, thermography and electrophysiologic study were similar in diagnostic sensitivity, and the 2 methods agreed on the presence or absence of abnormality in 71% of cases. However, the thermographic findings had limited localizing value. Relative limb warming was often seen in patients with acute denervation on EMG, and limb cooling in those with more chronic lesions, but the side of the root lesion could not be identified confidently by thermography alone. Moreover, thermographic abnormalities appeared not to follow a dermatomal distribution and failed to identify the clinical or electrophysiologic level of radiculopathy in most cases. Thus, the thermographic findings are nonspecific, of little diagnostic value, and of uncertain prognostic relevance.

Adult↗
PubMed1988

Subacute structural myopathy associated with human immunodeficiency virus infection.

An unusual myopathy characterized by selective loss of thick filaments and widespread formation of rod bodies is described in two men, both seropositive for human immunodeficiency virus. We were unable to find any previous reports documenting this combination of morphological abnormalities, which we believe may be related to human immunodeficiency virus infection. Both patients responded to treatment: one, to steroid therapy; the other, to plasmapheresis.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Peripheral neuropathy associated with acquired immunodeficiency syndrome. Prevalence and clinical features from a population-based survey.

We prospectively studied 40 hospitalized patients who had well-established diagnoses of acquired immunodeficiency syndrome. Patients with confounding risk factors for neuropathy were excluded; none of the study patients had known vitamin deficiency, alcoholism, or any metabolic, drug, or toxic factor. Clinical and electrophysiologic evidence of a distal symmetric polyneuropathy was found in 35% (13/37) of the patients. Symptoms and signs of neuropathy were usually mild, and painful dysesthesias were uncommon. Amplitude reduction of sural nerve action potentials distinguished all patients with from those without clinical neuropathy. Results of other electrophysiologic studies of sural, peroneal, and median nerves were typically normal. These results provide evidence of distal axonal degeneration. Neuropathy occurred only in patients with systemic illness longer than five months' duration. When compared with patients without neuropathy, these patients had more severe weight loss and a higher incidence of clinical dementia. Follow-up evaluation showed no evidence of clinical progression over a six-month period. The pathogenesis of this common distal axonal polyneuropathy is unknown and warrants further investigation.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Magnetic resonance imaging in amyotrophic lateral sclerosis.

Magnetic resonance imaging (MRI) was used in 5 patients with clinically definite amyotrophic lateral sclerosis to determine the frequency of central white matter abnormalities. Two patients had symmetrical areas of increased signal intensity seen on MRI extending from the cortex, through the corona radiata, posterior limb of the internal capsule, and cerebral peduncles into the pons. These MRI abnormalities presumably relate to the pathological changes observed by others in the central white matter of patients with amyotrophic lateral sclerosis.

Adult↗
PubMed1988

AAEE case report #15: ulnar neuropathy at or distal to the wrist.

A 56-year-old woman developed insidiously progressive, painless weakness of her left hand. Clinical and electrodiagnostic abnormalities were limited to the motor function of the hand, with the hypothenar less affected than more distal ulnar muscles. Compression of the distal ulnar nerve by a ganglionic cyst was surgically relieved and there was postoperative improvement. The electrodiagnosis of ulnar neuropathy at or distal to the wrist is reviewed together with relevant anatomic and clinical aspects of these uncommon lesions.

Electromyography↗
PubMed1988

Neuromuscular effects distant from the site of botulinum neurotoxin injection.

We assessed the severity and temporal profile of distant neuromuscular effects from a single dose (280 units) of botulinum neurotoxin injected into neck muscles for torticollis. We performed single-fiber EMG studies on the biceps brachii of six patients to measure jitter (20 pairs) and fiber density on the initial treatment day and then again, at least once more, after 2 to 12 weeks. No patient developed weakness beyond the neck muscles or decrement of the biceps response to repetitive 3-Hz nerve stimulation. Between the baseline and the last follow-up study, the average of mean MCD increased from 29 microseconds to 38 microseconds (31%). Mean fiber density increased concurrently or earlier from 1.35 to 1.79 (33%). There were no electrophysiologic signs of presynaptic blockade, even at 2 and 4 weeks. The effects we observed are compatible with stimulation of terminal sprouting by the neurotoxin, without significant presynaptic inhibition of acetylcholine release. We therefore believe that higher dosages of the neurotoxin may be used if clinically indicated.

Adult↗
PubMed1988

Relative utility of different electrophysiologic techniques in the evaluation of brachial plexopathies.

We report the results of detailed electrophysiologic studies in 23 patients with suspected brachial plexopathies. In five with neurogenic thoracic outlet syndrome, needle EMG and determination of size of ulnar sensory nerve action potentials (SNAPs) and thenar M waves were important in localizing the lesion; F-response and somatosensory evoked potential (SEP) studies were of more limited utility. All electrodiagnostic studies were normal in 10 patients with nonneurogenic thoracic outlet syndrome. In traumatic (three patients) or idiopathic brachial plexopathy (five patients), needle EMG was especially helpful but, in the former, SEP studies helped to guide management and, in the latter, to confirm the proximal site of the lesion when peripheral SNAPs were normal. The presence of preserved but small SNAPs but absent M waves in patients with traumatic plexopathies suggested a combined pre- and postganglionic lesion.

Action Potentials↗
PubMed1987

The effect of temporal dispersion on compound action potential area in human peripheral nerve.

In 32 ulnar nerves of healthy volunteers, the mean area of the compound muscle action potential recorded over abductor digiti minimi was reduced by 7.4% when comparing above-elbow with wrist stimulation and by 1.9% when comparing above-elbow with below-elbow stimulation. In 20 of these nerves, the mean area of the compound nerve action potential (CNAP) recorded over the fifth digit was reduced by 36% when comparing above-elbow with wrist stimulation. Area reduction of the compound action potential, especially of the CNAP, appears to be a characteristic effect of temporal dispersion in peripheral nerve when utilizing the bipolar recording technique routinely employed in clinical neurophysiology. A thorough understanding of the effects caused by temporal dispersion and of their quantitative limits in normal peripheral nerve is important for the proper interpretation of nerve conduction studies.

Adult↗
PubMed1985

Ulnar nerve conduction study of the first dorsal interosseous muscle.

Ulnar neuropathy at or distal to the wrist is difficult to diagnose. Sensation is normal in the majority of cases, and the interosseous muscles are usually more severely involved than are the hypothenar muscles. A technique for ulnar nerve conduction study of the first dorsal interosseous muscle is described, and normal values based upon 373 studies are presented. Using this technique the upper limit for distal motor latency (DML) to the first dorsal interosseous (FDI) muscle is 4.5 ms. More precisely, DML to the FDI should not exceed DML to the contralateral FDI by more than 1.3 ms, nor should this value exceed the DML to the ipsilateral abductor digiti minimi by more than 2.0 ms. The lower limit for amplitude of the compound muscle action potential recorded over FDI is 6mV. If motor conduction study of the first dorsal interosseous muscle is more routinely performed, earlier and more frequent recognition could be followed by improved surgical remediation of this compression neuropathy.

Action Potentials↗
PubMed1984

Conduction block in compression neuropathy: recognition and quantification.

Previous reports of conduction block in compression neuropathy have used the amplitude difference of the compound muscle action potential (CMAP) comparing proximal with distal stimulation. The present study was undertaken to determine if area reduction of the proximal CMAP provides diagnostic information that is not included in amplitude reduction, particularly in distinguishing conduction block from temporal dispersion. Digitized, integrated area measurements were compared with amplitude and, as a convenient estimate of area, the calculated M-index (1/2 duration X amplitude). Amplitude reduction did not reliably distinguish conduction block from temporal dispersion in compression neuropathy. Both in the investigation of conduction block and in the management of compression neuropathy, integrated area measurement allows for the more accurate identification and quantification of conduction--a usually reversible cause for weakness in compression neuropathy.

Action Potentials↗
PubMed1984

Absence spells. Hyperventilation syndrome as a previously unrecognized cause.

Absence spells in adults have been recognized in association with disorders of excessive somnolence, transient ischemia of the temporal lobes, and seizure disorders. A 66-year-old man who presented with a history of absence spells for more than 20 years is described. After diagnosis of a hyperventilation syndrome without an associated seizure disorder, educational and behavioral therapy without the use of medication has produced a long, continuing remission of these spells. The hyperventilation syndrome continues to present in many ways, often without recognition by physicians for prolonged periods. The case presented exemplifies this problem and may be the first report of absence spells caused by hyperventilation.

Aged↗
PubMed1972

Mescaline.

Explore the source record for details and available documents.

Animals↗
PubMedDate not supplied

Peripheral neuropathy associated with disulfiram administration.

Very few cases of peripheral neuropathy as a complication of disulfiram therapy have been described. The clinical and electrodiagnostic features of two patients who developed a severe peripheral neuropathy during disulfiram administration are reported. Evidence is presented which suggests that disulfiram causes a dying-back axonal neuropathy.

Action Potentials↗